UNIVERSITY  OF  CALIFORNIA  Agricultural  experiment  Station 

COLLEGE    OF    AGRICULTURE  E.    W.    HILGARD,    DIRECTOR 

BERKELEY,  CALIFORNIA 


CIRCULAR  No.  10. 

(March,  1904.) 


READING  COURSE  IN  ECONOMIC  ENTOMOLOGY. 


By  C.  W.  WOODWORTH. 


(The  work  of  the  Experiment  Station  is  generally  quite  distinct  from  that  of  the 
Department  of  University  Extension  in  Agriculture,  but  in  this  instance  it  seemed  wise 
to  issue  a  joint  publication.  It  concerns  primarily  the  work  of  the  latter  department, 
but  is  also  intended  for  the  training  and  direction  of  a  set  of  reliable  volunteer  observers 
through  whom  the  Station  may  expect  to  secure  valuable  data  not  otherwise  easily 
obtainable.) 

The  desire  has  been  very  widely  expressed  for  individual  or  class 
instruction  along  agricultural  lines  by  those  unable  to  attend  the 
University.  One  of  the  topics  upon  which  inquiry  has  been  particu- 
larly made  is  that  of  Economic  Entomology.  We  have  decided,  there- 
fore, to  offer  a  reading  course  in  this  subject  calculated  to  give  the 
student  a  broad  general  knowledge  of  the  facts  of  the  science,  and  an 
acquaintance  with  the  most  recent  publications  of  the  working  economic 
entomologists  of  the  country. 

GENERAL    DIRECTIONS. 

Those  desiring  to  enroll  as  readers  should  make  application  to 
W.  T.  Clarke,  Assistant  Superintendent,  University  Extension  in 
Agriculture,  Berkeley,  California.  Each  reader  will  be  furnished  with 
a  set  of  bulletins  which  will  serve  as  text-book.  He  will  be  expected  to 
make  himself  thoroughly  familiar  with  their  contents.  A  circulating 
library  is  also  provided,  for  collateral  reading  and  reference.  These 
books  should  be  read  as  carefully  as  possible  in  accordance  with  the  direc- 
tions given  in  this  circular.  After  the  completion  of  the  work  here 
outlined,  an  examination  will  be  arranged  for  with  an  instructor  in  the 
Entomological  Department. 

Those  who  thus  complete  this  course  will  be  eligible  to  advanced 
standing  in  Economic  Entomology  should  they  subsequently  enter  the 
University.  This  course  may,  therefore,  be  considered  a  University 
course  given  in  absentia,  and  must  be  pursued  with  the  same  care  and 
thoroughness  as  though  done  in  the  class-rooms  at  Berkeley.  The 
names  of  those  completing  this  course  will  be  kept  as  a  special  mailing 


—  2  — 

list,  and  they  will  receive  thereafter  not  only  the  bulletins  of  the  Experi- 
ment Station,  but  also  all  circulars  and  notices  of  special  publications 
of  the  Entomological  Department. 

Those  reading  in  this  course  by  themselves  will  receive  the  books 
forming  the  reference  library,  one  at  a  time  by  express,  and  will  be 
required  to  pay  the  express  charges  both  ways.  There  will  be  no  fees 
or  other  charges  to  be  paid  by  the  student,  except  for  damage  to  books 
beyond  reasonable  wear.  The  Entomological  Department  will  attempt 
to  answer  letters  of  inquiry  of  readers  in  this  course,  and  to  assist  them 
in  any  difficulties  they  may  find  in  their  studies. 

Reading  Circle. — It  is  strongly  recommended  that  wherever  possible 
a  reading  circle  be  formed  for  mutual  helpfulness  in  this  study.  Where 
this  is  done,  the  whole  reference  library  will  be  sent  to  the  member 
designated  by  the  circle,  and  the  distribution  can  be  arranged  to  suit 
the  convenience  of  the  members.  We  would  suggest  that  the  circle  form 
an  organization,  charging  a  sum  for  membership  sufficient  to  raise  a 
fund  not  only  to  pay  the  express  charges  on  the  circulating  library,  but 
also  to  buy  a  few  books  on  the  subject  for  the  local  library  or  as  a 
nucleus  for  a  public  library,  if  one  is  not  already  in  existence  in  the 
community.     Thus  the  work  of  the  circle  will  become  more  permanent. 

Another  advantage  of  the  organization  of  a  reading  circle  will  be  the 
possibility  of  personal  instruction  by  a  visit,  to  the  community,  of  a 
member  of  the  staff  of  the  Entomological  Department.  Where  possible 
some  such  arrangement  as  the  following  will  be  made:  After  the  com- 
pletion of  the  course  by  a  circle  a  date  will  be  arranged  for  this  visit. 
The  instructor  will  spend  half  a  day  with  the  members  of  the  class, 
visiting  orchards  and  studying  the  insect  pests  out  of  doors.  Another 
half  day  will  be  spent  with  those  who  have  followed  the  course,  in 
answering  questions  and  discussing  difficulties  met  with  by  members  of 
the  class,  and  in  holding  the  examination.  The  evening  may  be  devoted 
to  a  public  lecture,  where  a  topic  of  general  interest  will  be  discussed. 

WHY    STUDY    THIS    SUBJECT. 

The  study  of  Economic  Entomology  appeals  more  or  less  strongly  to 
a  large  number  of  people  and  is  valuable  for  two  important  reasons: 
its  educational  value  and  its  economic  value. 

Educational  Value. — The  importance  of  the  educational  value  of  this 
study  may  be  overlooked  at  first  sight  by  the  practical  grower,  but  he 
will  be  none  the  less  ready  to  acknowledge  its  claim  when  it  is  clearly 
seen.  What  is  meant  by  the  educational  value  of  a  study  is  the  develop- 
ment of  power  that  arises  from  it.  If  one  can  become  more  able  to 
observe  clearly,  to  quickly  comprehend  the  significance  of  what  he  sees 
in  the  practical  problem  he  has  in  hand,  and  learns  how  to  direct  his 


—  3  — 

observations  so  that  he  will  obtain  the  facts  needed  for  the  solution  of 
his  problem,  these  are  qualities  of  high  educational  value  whose  impor- 
tance no  one  can  question.  Economic  Entomology  is  full  of  problems 
of  every  degree  of  difficulty  inviting  the  student  ever  onward.  It  will 
be  attractive,  therefore,  to  many  primarily  from  the  motive  of  its  educa- 
tional value,  and  this  motive  should  influence — indeed,  largely  shape 
the  method  of  study  of  every  student.  Do  not  study  for  "  general  infor- 
mation," making  the  mind  simply  a  warehouse  for  the  storing  of 
miscellaneous  facts  to  no  definite  purpose,  but  seek  for  power  to  know, 
to  select,  and  to  use  facts. 

Economic  Value. — Most  persons  are  well  aware  that  the  economic 
importance  of  insects  is  enormous,  and  look  to  Economic  Entomology  for 
a  relief  from  their  ravages.  Some  confuse  Entomology  with  Economic 
Entomology,  and  have  lost  sight  of  the  fact  that  the  latter  is  a  depart- 
ment of  economics  and  has  to  deal  primarily  with  questions  of  money 
values.  Whenever  the  quality  or  quantity  of  an  agricultural  product 
is  diminished  by  the  presence  or  activities  of  insects,  it  is  only  in  such 
cases  that  we  have  a  problem  in  Economic  Entomology. 

The  solution  of  the  problems  of  this  science  consists  in  finding  ways 
and  means  of  avoiding  some  of  the  losses  due  to  insects,  with,  at  the 
same  time,  a  relatively  small  expenditure,  the  index  of  the  success 
being  the  amount  of  money  constituting  the  difference  between  cost  and 
saving  secured. 

Strive  to  keep  these  facts  always  in  mind,  endeavoring  to  develop 
sound  judgment  as  to  the  money  value  of  that  destroyed  by  insects, 
and  the  degree  of  probability  of  loss  by  their  future  attacks. 

HOW    TO    STUDY. 

In  this  reading  course  the  error  one  will  be  most  liable  to  make  is  to 
fail  to  connect  what  he  reads  with  his  own  experience.  Every  one  has 
had  more  or  less  acquaintance  with  insects  and  their  work.  If  one  fails 
to  recognize  each  of  his  old  acquaintances  as  he  reads  about  them  he 
misses  by  just  so  much  the  purpose  of  this  study.  The  reader  should 
ask  himself  as  each  insect  is  discussed,  "Where  have  I  met  this  crea- 
ture?" And  as  each  fact  is  brought  forth,  the  further  question  should 
be,  "Was  this  my  experience?"  Reading  in  this  way,  that  which 
would  otherwise  be  dry  and  meaningless  becomes  full  of  interest. 

Further  than  this  the  student  should  begin  to  observe  insects  more 
earnestly  than  ever  before.  Every  statement  one  finds  in  the  books 
that  he  can  readily  verify  he  should  strive  to  determine  for  himself. 
Every  insect  in  the  field  holds  something  of  value  to  be  discovered  by 
the  earnest  student.  Let  one's  reading  become  a  key  to  nature,  for  it  is 
nothing  apart  from  nature. 

In  an  attempt  to  study  insects  in  connection  with  the  reading,  the 


greatest  difficulty  that  will  be  met  with  is  the  small  size  of  the  creatures 
studied.  A  great  deal  can  be  learned,  even  about  the  smallest  forms, 
with  the  unaided  eye;  but  the  use  of  a  good  hand  magnifier  will  open 
ii])  a  new  world  to  the  student. 

How  to  Select  a  Magnifier. — Do  not  choose  a  lens  of  large  size.  The 
magnifying  power  is  generally  greater  the  smaller  the  size  of  the  lens. 
For  the  work  proposed  in  this  course  we  would  recommend  a  f-inch 
Coddington  lens.  This  can  be  obtained  through  any  dealer  in  optical 
goods.  In  choosing  a  lens  the  student  should  know  that  freedom  from 
aberation  is  the  quality  most  to  be  sought  after.  Aberation  is  of  two 
kinds,  chromatic  and  spherical. 

Chromatic  aberation  may  be  detected  by  first  putting  the  lens  very 
close  to  a  printed  page  and  slowly  withdrawing  it.  As  the  letters  begin 
to  lose  their  distinctness  more  or  less  color  will  be  seen  around  them. 
A  lens  should  be  rejected  if  these  rainbow  colors  are  very  pronounced. 

Spherical  aberation  may  be  seen  when  the  lens  is  removed  still  farther 
from  the  paper,  when  the  letters  will  appear  distinct  again,  but  small 
and  upside  down.  Now  if  the  lines  are  straight  and  not  closer  together 
at  the  edges  the  lens  is  of  good  quality  in  this  respect. 

How  to  Use  a  Magnifier. — After  one  has  obtained  a  lens  he  will  have 
to  use  it  the  right  way  to  get  the  best  results.  The  most  important 
thing  is  to  see  that  the  point  at  which  one  desires  to  look  is  in  the  light. 
One  must  not  allow  the  head  or  the  lens  to  throw  a  shadow  on  the 
object  and  then  expect  to  see  plainly. 

The  next  most  important  thing  is  to  hold  all  steady.  The  best  plan 
is  to  lay  the  two  hands  against  each  other,  one  holding  the  object  and 
the  other  the  lens,  and  bring  the  cheek  against  the  hand,  with  the  eye 
as  close  to  the  lens  as  possible. 

LIFE    HISTORIES    OF    INSECTS. 

Next  in  importance  to  the  obtaining  of  that  familiarity  with  the 
structure  of  insects  that  will  enable  us  to  recognize  any  particular  kind, 
is  an  acquaintance  with  the  facts  of  its  growth  and  development  and 
with  the  relation  it  bears  to  the  season. 

Moulting — The  most  important  fact  in  the  structure  of  an  insect  is 
the  hardening  of  the  skin  to  serve  as  its  skeleton.  This  makes  neces- 
sary the  process  known  as  moulting,  whereby  the  hardened  outer  skin 
is  cast  off,  so  as  to  permit  the  enlargement  of  the  body  to  meet  the 
necessities  of  growth.  All  insects  go  through  this  process  a  number  of 
times  before  they  become  full  grown.  The  detail  of  the  process  varies 
greatly  among  the  different  insects,  and  may  be  very  different  in  the 
earlier  and  later  moults.  If  the  student  has  not  already  observed  the 
process  he  should  cage  a  caterpillar  in  a  tumbler,  or  other  convenient 


receptacle,  providing  it  with  fresh  food  and  keeping  it  under  observa- 
tion until  a  moult  occurs.  The  approach  of  the  moulting  period  may 
be  known  by  the  insect  refusing  food. 

Practically  all  the  changes  in  structure  or  in  the  size  of  the  hard 
parts  of  the  body  are  brought  about  at  the  time  of  the  moult,  and  the 
change  is,  therefore,  sudden.  The  most  important  moult  is  usually  the 
last  one,  for  at  this  time  the  wings  and  other  adult  structures  are 
perfected. 

Metamorphosis. — The  change  that  occurs  during  the  life  of  an  insect, 
through  its  various  moults,  is  called  its  metamorphosis.  We  can  dis- 
tinguish three  types  of  metamorphosis: 

1.  Primitive,  in  which  the  change  at  each  moult  is  only  moderate 
in  amount. 

2.  Simple,  where  the  change  at  the  last  moult  has  come  to  be  much 
more  profound  than  at  any  of  the  others,  on  account  of  the  develop- 
ment of  wings.  This  is  often  called  incomplete  metamorphosis,  though 
the  term  simple  is  much  more  satisfactory. 

3.  Complex;  two  moults  being  required  to  accomplish  the  change 
from  the  young  to  the  adult  condition,  the  stage  between  these  two 
moults  is  entirely  occupied  in  accomplishing  the  reorganization  of  struc- 
ture, and  the  insect  is  incapable  of  taking  food  during  this  interval.  The 
term  complete  metamorphosis  is  often  applied  to  this  type  of  transfor- 
mation. 

The  periods  of  life  of  an  insect  are  designated  as  follows: 
With  Primitive  Metamorphosis:  egg  insect 


With    Simple    Metamorphosis:  egg  nymph  imago 


With  Complex  Metamorphosis:  egg     larva  pupa  imago 

Annual  History. — The  possession  of  metamorphosis  permits  insects 
to  adapt  themselves  so  well  to  the  changing  conditions  of  the  seasons 
that  it  may  be  that  the  seasons  are  largely  responsible  for  the  develop- 
ment of  this  course  of  life.  At  any  rate,  the  annual  history  of  an  insect, 
by  which  we  mean  the  condition  of  development  of  the  insect  during 
the  different  portions  of  the  year,  is  the  most  important  study  to  be 
made  preliminary  to  the  mapping  out  of  a  plan  of  campaign  against 
it.  How  important  this  matter  is  may  be  seen  by  carefully  reading  the 
account  of  the  vine  hopper,  the  potato  worm,  the  peach  worm,  and  the 
codling  moth,  or  of  almost  any  of  the  injurious  insects. 

In  one's  reading  and  in  his  study  of  insects  in  the  field  the  first  work 
should  be  to  get  a  clear  idea  of  the  annual  history  of  the  insect  under 
consideration.  A  good  plan  is  to  construct  a  diagram  something  like 
that  given  for  the  peach  worm.* 


*  Bulletin  No.  144,  p.  32. 


—  6  — 

Careful  observation  in  the  field  during  one  year  should  be  sufficient 
'to  gain  a  fairly  complete  annual  history  of  an  insect,  unless  it  presents 
peculiar  difficulties.  Sometimes  it  is  rather  difficult  to  follow  an  insect 
at  a  particular  season.  Some  plant  lice,  for  instance,  at  the  period  of 
migration  experience  a  great  mortality,  and  from  excessive  abundance 
may  in  a  week  become  so  scarce  that  a  very  careful  search  fails  to 
reveal  them  anywhere.  Perhaps  the  next  spring  they  may  reappear  in 
an  equally  mysterious  manner  and  increase  to  excessive  numbers  again 
by  fall. 

Possibly  some  of  these  cases  would  become  less  mysterious  if  we 
made  use  of  cages  to  confine  some  of  the  insects  so  as  to  watch  the 
development  so  closely  that  we  would  with  certainty  recognize  the 
insect  in  all  its  stages.  This  is  almost  essential  in  the  case  of  insects 
with  complex  metamorphosis,  since  the  change  from  larva  to  pupa  and 
from  pupa  to  imago  is  so  great  that  one  can  not  safely  connect  the  dif- 
ferent stages  of  the  same  insect  without  positive  proof. 

Any  kind  of  tight  receptacle  will  do  for  a  breeding  cage  to  make 
these  determinations.  Glassware,  such  as  tumblers  or  lamp  chimneys, 
will  be  found  very  satisfactory  for  this  purpose.  Food  should  be  kept 
fresh  and  all  the  conditions  maintained  as  normal  as  possible. 

CLASSIFICATION    OF    INSECTS. 

The  student  should  make  himself  acquainted  with  the  classification 
of  insects,  so  that  he  may  intelligently  follow  the  literature  of  ento- 
mology, and  because  the  insects  belonging  to  a  particular  group  have 
a  blood  relationship  with  each  other,  and  the  knowledge  gained  about 
one  member  of  a  group  will  be  full  of  suggestions  to  the  student  when 
he  attempts  to  master  another. 

Insect  Names. — For  the  purpose  of  accurately  designating  insects  a 
system  of  technical  names  has  been  adopted  by  naturalists.  The  full 
technical  name  of  an  insect  consists  of  three  parts:  (1)  the  genus 
name,  which  is  usually  derived  from  a  Greek  substantive,  and  always 
begins  with  a  capital  letter;  (2)  the  species  name,  usually  a  Latin 
adjective  corresponding  in  gender  with  the  genus  name,  and  beginning 
with  a  small  letter*;  and  (3)  the  authority,  an  abbreviation  of  the 
name  of  the  original  describer  of  the  insect. 

Thus  one  of  our  commonest  grasshoppers  bears  the  name  (Edaleonotus 
enigma  Scud.,  which  might  be  translated  into  English  as  Scudder's 
puzzling  Swollen-back. 

*A  common  usage  is  to  capitalize  those  specific  names  which  have  been  derived  from 
proper  names,  but  the  rule  of  never  capitalizing  specific  names,  as  adopted  in  this  cir- 
cular, is  preferable. 


Synonyms. — Unfortunately,  many  insects  have  received  a  number  of 
names.  The  rule  has  been  established  that  the  first  specific  name  given* 
to  an  insect,  if  it  does  not  already  belong  to  another  of  the  same  genus, 
should  always  be  retained  as  its  true  name.  Often,  however,  some  one 
else  may  give  it  another  name,  either  because  he  did  not  know  of  the 
first  name  or  because  he  thought  he  had  a  different  insect.  The  new 
name,  of  course,  can  not  hold,  even  though  it  may  have  come  into 
general  use. 

Another  source  of  synonyms  is  the  placing  of  the  species  name  with 
the  wrong  genus  name.  All  the  species  in  a  genus  should  be  very 
closely  related  with  one  another,  and  if  a  species  is  placed  where  it 
really  does  not  belong  it  must  be  changed. 

Group  Names. — A  scheme  has  become  generally  adopted  of  indicating 
the  groups  of  insects  by  using  a  genus  name  with  a  special  termination; 
thus, 

Genus,         Acridium. 

Tribe,  Acridiini.' 

Subfamily,  Acridiinae. 

Family,        Acridiidsf. 
There  are  several  other  group-terminations  that  will  be  occasionally 
met  with,  but  which  are  not  as  yet  generally  adopted. 

Orders  of  Insects. — The  primary  division  of  insects  is  into  Orders. 
The  names  of  the  orders  were  given  before  any  one  had  the  idea  of 
using  derivative  group  names.  The  names  of  the  principal  orders  end 
in  -ptera,  meaning  wing,  because  Linnaeus,  who  gave  these  names, 
separated  the  orders  by  peculiarities  of  their  wings. 

There  is  much  difference  of  opinion  as  to  how  many  orders  should  be 
recognized.  These  differences  of  opinion  are  entirely  in  reference  to  the 
smaller  groups.  All  are  practically  agreed  about  the  greater  orders. 
The  six  large  orders  are: 

Orthoptera       =  Grasshoppers,  etc. 

Hemiptera       =  Bugs,  plant  lice,  scale  insects,  etc. 

Coleoptera       =  Beetles. 

Diptera  =  Flies. 

Hymenoptera  =  Wasps  and  bees. 

Lepidoptera  =  Butterflies  and  moths. 
The  student  should  get  these  six  groups  thoroughly  well  fixed  in  his 
mind,  so  that  he  can  recognize  a  figure  or  a  specimen  of  the  adult 
insect.  The  structure  of  the  mouth-parts  and  of  the  wings  should 
receive  attention.  He  should  also  understand  about  the  metamor- 
phosis of  each  group  and  recognize  the  young  insect. 
The  minor  groups  consist  of:  • 

Aptera.  Minute  wingless  insects,  now  generally  recognized  as  forming  a  distinct 
order ;  none  are  of  much  economic  significance. 


Odonata,  the  dragon  flies  and  damsel  flies,  aquatic  as  nymphs  and  predaceous 
throughout  their  life.  Often  counted  a  distinct  order,  but  sometimes  united  with  other 
aquatic  insects. 

Ephemerida,  May  flies;  aquatic  forms,  which  are  short-lived  and  do  not  take  food  as 
adults.  None  are  of  economic  importance.  Often  counted  a  distinct  order,  but  some- 
times united  with  other  aquatic  insects. 

Plecoptera,  the  family  Perlidss,  aquatic  insects  of  no  economic  importance;  are  some- 
times counted  a  distinct  order. 

Forficulidie.  The  earwigs  usually  placed  with  the  Orthoptera,  but  sometimes  sepa- 
rated by  themselves;  have  subterranean  habits  and  are  of  but  little  economic  impor- 
tance. 

Isopoda.  The  family  Termitidse,  the  white  ants,  is  very  injurious  in  the  tropics,  but 
rarely  in  the  temperate  zone.     The  group  is  commonly  united  with  the  following. 

Corrodentia.  The  family  Psocidx,  including  only  insects  of  no  economic  importance, 
is  often  considered  a  distinct  order. 

Mallophaga.  The  bird  lice  are  very  commonly  considered  a  distinct  order,  but  are  in 
reality  quite  close  to  Psocidee,  and  might  be  included  in  the  former  group. 

Physopoda.  These  minute  insects  are  the  true  thrips,  and  are  often  highly  injurious 
to  cultivated  plants.  They  are  very  commonly  counted  as  a  distinct  order,  but  are  cer- 
tainly allied  to  the  Hemiptera  and  are  often  included  among  them.  A  few  authors 
place  them  in  the  Neuroptera,  which  is  made  to  include  all  insects  not  in  the  six  major 
orders. 

Pediculida'.  The  true  lice  have  usually  been  grouped  with  the  Hemiptera,  with 
which  they  are  certainly  closely  allied ;  but  some  authors  have  united  them  with  the 
Mallophaga,  and  others  have  made  them  an  order  by  themselves. 

Sialidx.  This  group  of  aquatic  insects  is  sometimes  made  an  order  by  itself  and 
very  generally  separated  from  the  Perlidse,  on  account  of  having  complex  metamor- 
phosis, though  in  other  particulars  it  is  closely  related.  The  group  is  not  economically 
important. 

Panorpidse  and  Hemerobiidix'.  These  families  of  terrestrial  insects  have  been  made  an 
order  by  some  entomologists,  though  commonly  classed  with  the  former  group,  to 
which  they  are  near  allies.  None  are  injurious;  a  few  may  be  of  some  value,  on 
account  of  their  predaceous  habits. 

Phryganxidx.  The  caddice  flies  are  aquatic  insects  forming  a  group  which  has  been 
given  rank  as  an  order  by  several  entomologists,  but  is  often  grouped  with  the  preced- 
ing.    They  are  of  no  economic  significance. 

Pulicidx.  The  fleas  have  been  made  a  distinct  order  by  some,  though  they  are  closely 
allied  with  the  Diptera  and  classed  in  that  order  by  most  authors. 

In  the  above  list  the  various  names  which  have  been  assigned  to 
these  minor  groups  have  not  been  given,  but  the  family  names  will 
enable  one  to  recognize  the  group  in  every  case. 

It  will  be  noticed  that  the  Physopoda  are  the  only  insects  in  this 
list  which  are  of  any  considerable  economic  importance  in  California, 
and  this  group  can  be  classed  with  the  Hemiptera.  The  six  larger 
groups,  therefore,  are  all  we  need  to  seriously  study  in  Economic 
Entomology. 

INSECTS    OF    CALIFORNIA. 

There  are  more  insects  known  to  occur  in  California  than  have  been 
listed  in  any  other  State.  The  great  majority  of  these  are  of  little  or 
no  economic  significance.  The  really  troublesome  forms  do  not  form  a 
very  large  list.  The  student  should  endeavor  to  gain  some  knowledge 
of  all  of  these.  As  a  guide  in  this  matter  the  following  enumeration  of 
injurious  forms  is  given: 


—  9  — 

Orthoptera. 

The  insects  in  this  group  are  mostly  vegetable-feeding  forms  and  are 
general  feeders;  that  is,  none  of  the  species  confine  their  attacks  to  a 
particular  plant,  as  is  so  common  with  the  higher  insects.  A  fairly 
complete  account  of  the  more  injurious  members  of  the  order  is  given 
in  Bulletin  No.  142;  some  of  the  less  important  forms  are  discussed  in 
the  reference  books.  The  injury  these  insects  do  to  plants  si  so  evident 
that  it  is  comparatively  easy  to  estimate  the  amount  of  loss  resulting 
from  their  attacks.  One  family,  the  Mantidae,  is  predaceous  and  has 
figured  to  some  extent  in  the  schemes  of  introducing  beneficial  insects 
to  attack  injurious  ones. 

Hemiptera. 

The  interest  in  this  group  centers  mainly  around  the  scale  insects 
and  plant  lice,  though  most  of  the  members  of  the  order  are  also  plant 
feeders  and  several  forms  are  highly  injurious.  A  few  bugs  are  pre- 
daceous, but  have  attracted  very  little  attention. 

All  the  vegetable-feeding  forms  obtain  their  food  by  sucking  the  juices 
of  plants,  and  it  is  very  difficult  to  determine  in  any  particular  case  the 
exact  amount  of  injury  to  be  expected  to  result  from  an  attack.  Up 
to  a  certain  point  the  presence  of  a  sap-sucking  insect  amounts  to 
nothing,  and  when  the  general  vigor  of  a  plant  is  good  and  the  con- 
ditions otherwise  favorable,  a  plant  can  stand  without  appreciable 
injury  what  would  in  other  cases  be  fatal  to  it. 

One  must  take  into  consideration  the  moisture  condition  of  a  plant 
as  well  as  the  numbers  of  the  insect  present. 

Another  factor  which  complicates  the  problem  is  the  sporadic  increase 
and  decrease  of  these  insects  which  is  often  noticed.  Many  of  them  are 
capable  of  increasing  with  incredible  rapidity  when  conditions  are 
favorable.  Since  we  do  not  know  exactly  what  these  conditions  are 
it  is  hard  to  say  whether  the  insect  in  question  will  reach  injurious 
numbers  or  not.  Again,  under  other  equally  unknown  conditions  not 
only  the  fecundity  may  suddenly  diminish,  but  the  life  of  a  greater  part 
of  the  individuals  may  be  lost  and  the  whole  economic  situation  be 
changed.  The  student  should  observe  with  greatest  care  the  evidences 
of  changes  of  this  kind,  and  may  be  able  to  add  materially  to  the 
knowledge  of  the  subject.  At  any  rate,  he  should  get  enough  acquaint- 
ance with  these  phenomena  to  cause  him  to  exercise  due  care  in  coming 
to  conclusions  in  regard  to  the  action  of  insecticides  or  of  any  other 
means  of  control  that  may  be  adopted.  A  very  good  experiment  which 
will  show  the  effect  of  external  conditions  upon  these  insects  may  be 
made  by  covering  the  top  and  three  sides  of  an  apple  tree  with  mos- 
quito netting  and  comparing  effect  on  the  woolly  aphis  as  contrasted 
with  adjacent  trees  in  the  orchard. 


—  10  — 

Physopoda.  Some  of  the  reference  books  give  a  very  good  general 
account  of  these  insects,  but  there  has  been  very  little  done  experiment- 
ally toward  their  control.  Those  favorably  located  for  making  observa- 
tions on  the  life  history  of  these  insects,  especially  their  wintering  habits, 
or  on  the  application  of  insecticides,  can  make  real  additions  to  our 
knowledge  of  the  subject. 

CoccidcY,  or  scale  insects,  have  done  a  great  deal  of  injury  in  this 
State,  and  the  San  Jose  scale  is  one  of  the  best  known  injurious  insects 
in  the  United  States.  The  reference  books  give  a  particularly  full 
account  of  this  insect  and  of  experimental  work  for  its  control.  This 
subject  deserves  very  careful  study.  Besides  the  San  Jose  scale  (Aspid- 
iotus  perniciosus  Corns.)  we  have  in  California  the  closely  allied  greedy 
scale  (A.  rapax  Corns.)  and  the  oleander  scale  {A.  hedrese  Vail.),  with 
much  the  same  habits,  but  hardly  as  injurious,  and  also  the  red  scale 
(Chrysomphalus  aurantii  Mask.)  of  the  orange.  The  long  scales,  the 
oyster-shell  scale  (Lepidosaphes  ulmi  Linn.)  of  the  apple  and  the  purple 
scale  (L.  beclii  Newm.)  of  the  orange,  are  really  also  quite  similar  in 
habits  to  the  above. 

Another  kind  of  scale  is  represented  by  the  black  scale  (Saisetia  olesc 
Bern.),  the  soft  brown  scale  (S.  hesperidum  Linn.),  the  brown  apricot 
scale  (Eulecanium  armeniacum  Craw),  and  the  pruinose  scale  (E.  prui- 
nosum  Coq.).  They  are  rather  better  protected  from  sprays  when  full 
grown  and  more  easily  killed  when  young  than  the  scale  insects 
formerly  enumerated.  The  development  of  the  smut  fungus  in  the 
excretia  of  these  insects  gives  them  additional  means  of  doing  injury  to 
fruits  and  ornamental  plants. 

The  cottony  cushion  scale  (Icerya  purchasi  Mask.),  which  is  usually 
controlled  by  the  imported  ladybird,  Vedalia  cardinalis,  forms  a  group 
quite  by  itself. 

Aleurodidse,  or  white  flies,  are  of  interest  chiefly  because  of  the  possi- 
bility of  the  introduction  of  the  injurious  orange  species  of  Florida,  as 
none  of  the  local  species  are  particularly  injurious.  One  of  the  green- 
house species  is  discussed  quite  fully  in  the  reference  books. 

Aphid  x.  Plant  lice  are  next  to  the  scale  insects  in  the  amount  of 
injury  produced.  Each  of  the  important  species  presents  problems 
peculiar  to  itself,  and  the  Eastern  accounts  of  these  insects  will  often 
not  apply  to  the  same  species  on  this  Coast. 

The  grape  phylloxera  (Phylloxera  vastatrix  Pla.)  is  the  only  species 
discussed  in  the  bulletins  of  this  Station,  and  is  the  most  injurious 
insect  of  this  group  in  the  State.  The  woolly  aphis  (Schizoneura  lani- 
gera  Haus.)  stands  next  to  the  codling-moth  as  the  most  injurious  apple 
insect.  It  is  entirely  different  from  the  phylloxera  in  habits  and 
character  of  injury,  but  like  the  latter  is  best  controlled  by  the  use  of 
resistant  roots. 


n 

— 11  — 

Other  important  species  are  the  hop  aphis  (Phorodon  humuli  Sch.), 
the  grain  aphis  (Nectarophora  avenae  Fabr.),  the  cabbage  aphis  (Aphis 
brassicae  Linn.),  and  the  black  peach  aphis  (Aphis  persicae  niger  Sm.). 
These  will  be  found  discussed  from  an  Eastern  standpoint  in  the  refer- 
ence books. 

Cicadina  indicates  a  number  of  families  of  mostly  minor  importance, 
but  in  the  family  Jassidtr,  the  leaf  hoppers,  there  are  a  considerable 
number  of  important  forms.  They  mostly  attack  grasses.  Two  spe- 
cies have  done  injury  to  grapevines  in  this  State,  one  of  which,  the 
vine  hopper  (Typhlocyba  comes  Say.),  is  very  troublesome.  It  is  dis- 
cussed in  Bulletin  No.  116. 

Heteroptera  includes  the  greater  part  of  the  larger  members  of  the 
order.  There  are  several  families  represented,  including  all  the  preda- 
ceous  forms,  several  of  which  became  famous  a  few  years  ago  under  the 
name  "kissing  bugs."  There  is  only  one  member  of  this  series  of  fami- 
lies that  may  be  considered  an  injurious  insect  of  first  class,  producing 
millions  of  dollars  of  loss  in  a  single  year.  It  is  the  chinch  bug  (Blis- 
sus  leucopterus  Say.),  and  will  be  found  fully  discussed  in  the  reference 
books.  This  is  an  interesting  case  for  the  economic  entomologist, 
because  while  it  has  been  known  on  this  Coast  for  years  it  has  never 
done  any  damage,  so  far  as  can  be  learned. 

We  have  several  injurious  species  belonging  to  this  group,  but  the 
only  ones  to  attract  much  attention  are  the  Harlequin  cabbage  bug 
(Mnrgantia  histrionica  Hahn.)  and  the  squash  bug  (Anasa  tristis  Del.). 

COLEOPTERA. 

The  beetles  include  nearly  half  of  the  known  insects,  but  there  is  no 
large  number  of  injurious  species.  The  habits  of  the  different  mem- 
bers of  the  order  are  very  diverse  and  must  be  considered  group  by 
group. 

The  Clavicomia  include  a  large  number  of  families  of  beetles,  most 
of  which  feed  on  decaying  substances.  None  of  the  California  repre- 
sentatives are  known  to  injure  growing  plants  except  some  of  the  lady- 
birds (Coccinellidse),  and  these  only  occasionally  and  to  a  slight  extent. 
The  usual  food  of  the  ladybirds  consists  of  plant  lice  and  scale  insects, 
and  are  considered  the  most  beneficial  members  of  the  entire  order. 
Some  Clavicomia  are  very  troublesome  pests  in  the  house  because  of 
their  feeding  on  furs,  woolens,  etc.,  and  one  species  (Sylvanus  surina- 
mensis  Linn.)  does  injury  to  stored  grain  and  to  dried  fruits. 

The  Phytophaga  are  all  vegetable  feeders.  The  family  Bruchidae 
includes  the  pea  weevil  (Bruchus  pisorum  Linn.)  and  the  bean  weevil 
(B.  obtecus  Say.),  both  of  which  are  injurious  in  this  State  as  in  the 
East.  The  family  Chrysomelidx  contains  the  flea  beetles,  various 
species  of  Phyllotreto,  Epitrix,  and  Haltica,  and  the  notorious  Diabrotica 
soror  Lee.      Many  other  species  are  occasionally  locally  troublesome. 


—  12  — 

The  wood  borers  (Cerambycidse)  are  abundant  in  some  parts  of  the 
State,  and  injurious  to  forest  and  shade  trees;  but  only  one — the  large 
Prionus  califomicus  Mots. — has  attracted  much  attention  as  attacking 
fruit  trees,  and  this  only  locally. 

Rhynchophora,  or  snout  beetles,  are  well  represented  on  this  Coast, 
and  though  they  are  practically  all  plant  feeders,  scarcely  any  have 
attracted  the  attention  of  horticulturists.  Two  closely  allied  species? 
Calandra  granaria  Linn,  and  C.  oryzse  Linn.,  the  grain  weevils,  are 
well  known  by  their  work  in  stored  grain.  Several  species  of  the  family 
Scalytidae  have  done  very  destructive  work  on  forest  and  shade  trees. 

Serricornia  include  a  rather  heterogeneous  series  of  families.  The 
wireworms  (Elateridm)  are  occasionally  destructive  to  the  roots  of 
truck  crops,  but  what  species  are  accountable  for  the  damage  has  not 
been  ascertained.  Of  the  BitprestidcT,  the  "  flat-headed  "  borer  ( Chrysobo- 
thris  femorata  Fab.)  easily  takes  first  place.  It  deserves  a  great  deal  of 
careful  study,  since  the  Eastern  recommendations  do  not  appear  to 
suffice  in  this  State.  This  and  other  species  sometimes  do  considerable 
damage  to  forest  and  shade  trees.  Several  of  the  Lampyridae  feed  on 
plant  lice,  and  none  of  the  family  are  injurious.  The  only  other  serri- 
corn  beetle  to  come  into  prominence  is  one  of  the  Ptinids?,  Polycaon 
confertus  Lee,  which  bores  holes  into  olive  twigs.  The  larvae  feed 
within  the  stumps  of  grapevines. 

Heteromera  are  unusually  well  represented  in  California,  but  with 
comparatively  few  injurious  forms,  practically  all  of  which  belong  to 
the  family  Meloidse.  These  are  known  as  blister  beetles.  They  are 
only  occasionally  present  in  destructive  numbers. 

Lamellicornia  include  a  number  of  mildly  injurious  insects.  The 
adult  of  several  species  of  Serica  and  Hoplia  have  attracted  consider- 
able attention  by  eating  the  leaves  and  buds  of  fruit  trees. 

Adephaga  are  practically  all  predaceous. 

Diptera. 

The  flies  are  probably  the  least  studied  of  the  larger  orders.  Many 
of  the  species  are  very  minute,  and  the  great  majority  live  on  decaying 
vegetable  matter  and  have  no  economic  significance. 

The  Cecidomyidse  include  the  Hessian  fly  (Cecidomyia  destructor  Say.) 
that  sometimes  does  some  injury  to  grain  in  the  Bay  region,  but  is  far 
from  being  the  pest  it  is  in  the  Eastern  States. 

The  Tipulidm  contain  a  few  species  that  occasionally  give  some 
concern  to  truck  farmers.  The  larvae  are  called  leather-jackets,  and 
sometimes  injure  the  roots  of  plants.  Which  species  are  concerned  has 
not  been  determined.  Several  families  contain  blood-sucking  species. 
Some  are  predaceous  and  others  parasitic. 

There  are  numerous  fruit  flies  in  other  countries  which  may  ulti- 
mately reach  here  and  revive  the  interest  in  this  order. 


13  — 


Hymenoptera. 


The  most  important  group  in  this  order  is  that  including  the  saw- 
flies.  Two  species  are  well  known  to  fruit-growers:  the  slug  of  the 
cherry  and  pear  (Eriocampa  cerasi  Peck.)  and  the  green  caterpillar  of 
the  pear  (Gymnonynchus  calif 'ornicus  Marl.),  the  latter  being  peculiar 
to  this  State,  but  having  much  the  same  habits  as  the  other,  which  is 
found  all  over  the  United  States. 

The  horntails  (Siricina)  and  the  gall  wasps  (Cynipina)  attack  mainly 
forest  and  ornamental  trees,  but  are  rarely  injurious. 

The  joint  worm  of  wheat  (Isosoma  tritici  Riley)  occasionally  does  a 
little  damage.  The  family  to  which  it  belongs,  and  all  the  related 
forms,  are  parasitic. 

Some  of  the  wasps  and  the  honey  bee  are  troublesome  on  ripe  fruit 
and  on  the  drying  grounds,  and  the  honey  bee  is  charged  with  sys- 
tematically spreading  the  dreaded  pear  blight. 

Lepidoptera. 

The  larvae  of  Lepidoptera  are  almost  exclusively  plant  feeders,  and 
include  a  large  part  of  the  injurious  species  attacking  cultivated  plants. 
They  are  nearly  all  controllable  by  the  use  of  arsenical  sprays,  so  that 
we  may  say  that  on  the  whole  they  are  better  controlled  than  most 
other  pests. 

Tineina  include  a  large  number  of  small  moths,  a  few  of  which  are 
troublesome  in  the  house;  such  as  the  clothes  moth  (Tinea  pellionella 
Linn.),  the  Mediterranean  flour  moth  (Ephestia  kuehniella  ZelL),  and  a 
number  of  others.  Those  most  injurious  to  plants  are  the  peach  worm 
(Anarsia  lineatella  ZelL),  the  potato  worm  (Phthorimsea  operculella 
ZelL),  the  codling  moth  (Carpocapsa  pomonella  Linn.),  and  the  peach- 
tree  borer  (Sanninoidea  opalescens  Edw.),  all  of  which  are  discussed  in 
the  bulletins  of  this  Station. 

Bombycina  average  larger  than  the  moths  of  the  preceding  group, 
and  include  over  half  of  the  members  of  the  order.  One  of  the  larger 
families  of  this  group  is  the  Geometridse.  The  larvae  of  these  moths 
walk  by  "looping,"  and  are  often  called  inchworms.  The  most  in- 
jurious member  of  the  family  is  the  cankerworm  (Paleacrita  vernata 
Peck.).  The  Noctuidse  is  the  largest  family  of  moths.  Many  species 
are  highly  injurious,  especially  the  groups  known  as  cutworms.  There 
are  quite  a  number  of  species  representing  several  genera.  Only  in  a 
comparatively  few  cases  have  our  species  been  bred  to  the  adult  con- 
dition so  that  they  could  be  determined.  Therefore,  we  do  not  know 
how  many  species  are  really  involved. 

The  S alumina  are  our  largest  moths,  but  do  not  include  any  that 
are  highly  injurious. 

The  Sphingina,  or  hawk  moths,  include  the  tomato  or  tobacco  worm 


—  14  — 

(Phlctjcthontius  sexta  John.),  and  the  so-called  armyworm  of  the  grape 
(Pholus  arJirmon  Drury). 

The  Rhopalocera,  or  butterflies,  are  not  generally  injurious;  the  cab- 
bage butterfly  (Pontia  rapse  Linn.)  being  an  exception. 

ACARINA. 

Besides  the  true  insects,  this  class  of  animals,  more  nearly  allied 
to  the  spider,  is  usually  considered  to  belong  to  the  domain  of  the 
economic  entomologist.  They  are  all  very  minute  creatures,  appro- 
priately called  mites;  some  of  which  attack  plants  and  produce  injury 
much  like  that  produced  by  insects. 

Phytopti  are  excessively  small  creatures,  and  include  the  rust  mites 
of  the  orange  (Phytoptus  sp.),  the  erinose  of  the  vine  (Phytoptus  vitis 
Land),  and  the  blister  mite  of  the  pear  (Phytoptus  pyri  Nal.),  all  strik- 
ingly different  from  each  other  in  the  appearance  of  the  affection  they 
produce  on  the  plant  they  infest. 

Tetranychi,  or  red  spiders,  are  still  more  injurious.  There  are  various 
species  of  Tetranychus  and  Bryobia,  usually  confused  with  each  other. 
One  species  of  each  of  these  genera  is  discussed  in  the  bulletins  of  this 
Station.  Much  remains  to  be  done  before  the  other  species  are  as  well 
known. 

INSECT   CONTROL. 

The  means  that  may  be  adopted  for  the  prevention  of  injuries  due  to 
insect  attack  require  as  careful  study  as  the  insects  themselves.  The 
student  should  observe  with  the  greatest  care  the  action  of  insecticides, 
and  in  every  experiment  arrange  checks,  that  is,  untreated  trees  or 
branches,  where  every  condition  will  be  comparable  with  the  treated 
trees. 

Many  valueless  materials  are  sold  as  insecticides,  and  the  dealers  are 
able  to  obtain  an  unlimited  number  of  testimonials  from  honest  men 
setting  forth  the  effectiveness  of  their  nostrum.  The  importance  of 
caution  and  scientific  accuracy  in  observations  of  this  kind  can  not  be 
too  strongly  insisted  upon. 

Diseases. — Attention  has  already  been  called  to  the  great  oscillations 
experienced  by  some  species  of  insects.  In  many  cases  the  cause  of 
this  can  be  quite  definitely  laid  to  the  effect  of  fungous  or  bacterial 
diseases.  Many  have  speculated  upon  the  possibility  of  using  these 
diseases  for  the  control  of  injurious  insects,  and  in  a  few  cases  consider- 
able progress  has  been  made.  In  the  case  of  the  chinch  bug,  for 
instance,  an  insect  for  which  no  ordinary  insecticide  is  available,  there 
have  been  notable  cases  of  the  most  complete  success  with  this  method. 
It  is  considered  a  thoroughly  unreliable  method,  however,  because  sue- 


—  15  — 

cess  depends  entirely  upon  the  occurrence  of  favorable  atmospheric 
conditions,  which  are  entirely  beyond  our  control.  When  these  condi- 
tions occur  the  diseases  commonly  appear  spontaneously  without  our 
assistance. 

For  these  reasons,  very  little  attention  is  now  being  given  to  this 
subject, 

Parasitic  and  Predaceous  Insects. — A  method  of  control  which  has 
always  been  looked  upon  with  a  great  deal  of  hope  is  that  of  using 
the  natural  insect  enemies  of  the  injurious  species.  From  the 
earliest  beginnings  of  economic  entomology,  much  attention  has  been 
given  to  the  study  of  parasites  and  predaceous  insects.  Various  meth- 
ods of  favoring  these  insect  allies  have  been  proposed  and  tried,  with 
no  very  flattering  results  until  a  large  number  of  Australian  insects 
collected  by  Messrs.  Koebele  and  Webster  were  introduced  into  the 
State  in  the  hope  that  something  might  be  done  to  aid  in  the  fight 
against  the  cottony  cushion  scale.  One  of  these,  a  ladybird  ( Vedalia 
cardinalis) ,  more  than  fulfilled  the  expectations  of  those  concerned  in 
its  introduction.  This  success  resulted  in  greatly  extended  efforts  along 
this  line.  Mr.  Koebele  and  our  State  Board  of  Horticulture  have  been 
untiring  in  their  work  in  this  direction,  and  while  no  such  success  as 
that  with  the  Vedalia  has  followed  their  efforts,  still  the  work  is  one 
deserving  much  more  attention  than  has  yet  been  given  to  it. 

From  the  nature  of  the  problems  involved,  it  can  not  be  undertaken 
profitably  by  individuals,  but  requires  the  expenditure  of  a  great  deal 
of  money. 

There  has  been  much  very  unreliable  matter  printed  concerning  this 
subject,  and  the  most  extravagant  statements  have  been  made  concern- 
ing insects  of  very  ordinary  degree  of  effectiveness.  It  requires  the 
most  careful  and  painstaking  observations  before  any  one  is  competent 
to  speak  intelligently  in  reference  to  the  effectiveness  of  an  introduced 
insect, 

Resistants. — A  third  method  of  combating  insects,  which  is  looked 
upon  with  a  great  deal  of  expectancy,  is  the  selection  or  development 
of  plants  upon  which  insects  can  not  or  will  not  feed.  Every  one  has 
noticed  plants  distasteful  to  insects  and  which  remained  untouched 
while  those  all  around  have  been  injured  by  them.  In  two  notable 
instances  this  has  been  made  use  of  with  the  best  of  results.  We  are 
only  at  the  beginning  of  work  along  this  line  and  can  only  guess  what 
may  be  brought  forth  by  careful  and  systematic  investigations. 

Remedies. — While  the  preceding  control-methods  may  wisely  receive 
the  attention  of  those  in  position  to  study  them,  that  with  which  the 
individual  grower  can  most  profitably  concern  himself  is  the  use  of 


—  16  — 

chemical  insecticides.  This  subject,  however,  need  not  be  discussed  in 
the  present  circular,  since  it  is  so  fully  treated  in  Circular  No.  7  of  this 
Station. 

CONCLUDING    REMARKS. 

The  purposes  of  this  course  will  be  largely  fulfilled  when  the  student 
obtains  sufficient  acquaintance  with  the  facts,  and  such  an  appreciation 
of  the  difficulties  of  accurate  observation  that  he  shall  approach  a 
problem  with  such  a  scientific,  conservative  spirit  that  he  will  not  be 
misled  by  appearances,  unsupported  by  definitely  ascertained  facts. 
Whether  or  not  this  will  be  accomplished  depends,  in  a  reading  course, 
upon  the  individual  reader;  since  he  will  not  have  the  assistance  of  the 
teacher's  personal  contact.  This  may  be  partly  compensated  for,  if  one 
is  a  member  of  a  reading  circle,  by  discussions  with  the  other  members 
of  the  circle.  Not  a  little  help  will  come  from  trying  to  put  one's 
impressions  into  writing.  For  this  purpose  the  following  set  of  ques- 
tions is  given  with  the  suggestion  that  each  reader  carefully  write  out 
answers  to  each  question,  following  his  reading  on  each  subject.  A 
comparison  of  the  answers  written  out  by  different  members  of  the 
circle  will  be  profitable.  This  set  of  questions  is  the  one  used  in  the 
Course  on  Economic  Entomology  at  Berkeley,  last  term.  They  were 
placed  in  the  hands  of  the  students  just  before  the  examination  and 
the  questions  actually  given  were  chosen  by  lot  from  this  list: 

Questions  foe  Course  in  Entomology — Agr.  lb. 

Scale  Insects.— (1)  Give  scientific  names  of  the  black  scale,  and  explain  construction 
of  such  names.  (2)  Describe  structure  of  black  scale.  (3)  Describe  mouth  parts,  and 
explain  manner  of  feeding.  (4)  How  are  scale  insects  distributed  from  plant  to  plant. 
(5)  Point  out  the  difference  in  structure  between  black  and  San  Jose  scales.  (6)  Give  a 
general  account  of  distillate  spraying;  (7)  of  resin  soap,  and  lime,  salt,  and  sulfur  mix- 
tures; (8)  of  cyanide  fumigation.  (9)  Discuss  the  use  of  parasites  and  predaceous 
insects  as  a  means  of  control. 

Other  He mipter a.— (10)  Give  a  general  account  of  the  woolly  aphis ;  (11)  of  the  phyllox- 
era; (12)  of  the  use  of  resistant  roots.  (13)  Give  method  of  control  of  leaf-inhabiting 
plant  lice.  (14)  Describe  injury  done  by  the  vine  hopper.  (15)  Give  its  life  history. 
(16)  Explain  difficulties  in  killing  it. 

Fruit  Worms.—  (17)  Describe  egg-laying  habits  of  codling-moth.  (18)  Process  of  hatch- 
ing and  entering  the  apple.  (19)  Describe  the  pupation.  (20)  Discuss  the  use  of  bands 
for  codling-moth.  (21)  The  method  of  spraying  with  paris  green.  (22)  Give  winter 
habits  of  the  peach  worm.  (23)  Explain  theory  of  spring  treatment  with  lime,  salt,  and 
sulfur.     (24)  Describe  summer  treatment  for  peach  worm. 

Other  Lepidoptera.— (25)  Give  life  history  of  the  peach-tree  borer.  (26)  Discuss  the 
gumming  of  the  peach  trees.  (27)  Describe  the  digging-out  process  of  treatment. 
(28)  Discuss  precautions  in  the  use  of  carbon  bisulfid.  (29)  Give  general  account  of  cut- 
worms. (30)  Discuss  the  remedies  for  cutworms.  (31)  Give  the  remedies  for  canker- 
worms. 

Grasshoppers. — (32)  What  is  meant  by  the  breeding-ground  of  migratory  grasshoppers? 
(33)  Distinguish  between  the  migratory  and  non-migratory  grasshoppers.  (34)  What 
remedies  are  available  on  the  breeding-grounds?  (35)  Describe  the  construction  and  use 
of  the  hopper-doser.    (36)  Give  an  account  of  the  use  of  poisoned  bait  for  grasshoppers. 


—  17  — 

Hymenoptera  and  Diptera. — (37)  Give  the  life  history  of  a  sawrly.  (38)  Explain  method 
of  treatment.  (39)  Describe  life  history  of  Hessian  fly.  (4(t)  Methods  of  preventing  its 
injury.     (41)  Describe  the  life  history  of  fruit  maggots ;  (42)  of  leather-jackets. 

Coleoptera.—{$&)  Discuss  means  of  control  of  white  grubs;  (44)  of  wireworms; 
(45)  of  borers. 

Mites.— (46)  Give  the  life  history  of  the  almond  mite;  (47)  of  the  red  spider  of  citrus 
trees.     (48)  Explain  the  effect  of  sulfur  sprays. 

INSTRUCTION    IN    ENTOMOLOGY    AT    BERKELEY. 

For  the  information  of  those  who  desire  to  continue  their  studies  in 
Entomology  at  the  University,  the  following  statement  of  the  work 
offered  in  this  department  in  the  Summer  Session,  Short  Course,  and 
Regular  Session,  respectively,  is  appended: 

In  the  Summer  Session,  July  to  August,  the  following  work  is  designed 
primarily  for  teachers  of  nature  study  in  secondary  schools: 

1.  Indoor  Nature  Work.  Lectures  and  demonstrations  illustrating 
the  study  of  insects  in  the  class-room. 

2.  Important  Insects.  Lectures  upon  those  insects  which  most  con- 
spicuously affect  the  interests  of  man. 

3.  Outdoor  Nature  Work.  A  series  of  excursions  for  the  study  of 
insects  in  the  field. 

4.  Classification  of  Insects.  This  course  is  designed  to  acquaint  the 
student  with  the  methods  of  finding  the  names  of  insects  and  to 
acquaint  him  with  the  literature  of  the  subject. 

5.  Methods  of  Microscopical  Study.  Designed  particularly  for 
advanced  students  or  those  owning  their  own  microscopes;  a  drill  in 
the  method  of  mounting  and  microscopical  observations. 

The  Short  Course  in  Agriculture  has  not  been  arranged  for  the 
coming  autumn.  The  work  in  Entomology  offered  last  fall  consisted  of 
a  course  of  lectures  on  Economic  Entomology  and  a  laboratory  course 
on  Scale  Insects.  A  special  announcement  can  be  had  upon  applica- 
tion next  August. 

The  Regular  Session  work  is  as  follows: 

4A.  Agriculture.  The  insects  affecting  field  crops  are  discussed  in 
connection  with  their  cultivation. 

4B.  Horticulture.  The  insects  affecting  the  various  fruit  crops  are 
discussed  as  each  fruit  is  considered. 

5D.  Viticulture.  The  insect  pests  of  the  vine  are  fully  treated  of  in 
this  course. 

7A.  General  Entomology.  A  rapid  review  of  the  classification, 
structure,  and  habits  of  insects. 

7B.  Economic  Entomology.  Review  of  the  insects  most  injurious  to 
agriculture  in  California. 

7C.     Ecology.     The  relation  of  insects  to  their  environment.     A  dis- 


—  18  — 

cussion  of  the  newer  lines  of  thought  concerning  the  evolution  of 
insects. 

7D.  Apiculture.  Practical  review  of  the  methods  and  problems  of 
modern  bee  keeping. 

8A.  Morphology  of  Insects.  A  laboratory  study  of  insect  structure, 
including  careful  drawing  and  dissection  of  a  series  of  typical  insects. 

8B.  Scale  Insects.  Detailed  study  of  the  structure  and  classifica- 
tion of  scale  insects,  and  the  methods  of  using  the  compound  microscope. 

8C.  Entomotaxy.  The  methods  of  collecting,  mounting,  and  deter- 
mining insects. 

8D.  Apiary  Work.  Actual  handling  of  bees  under  apiary  conditions, 
and  experiments  with  bees  in  observation  hives. 

9B.  Insecticides  and  Fungicides.  The  composition  and  compound- 
ing of  remedies. 

9C.  Spraying.  A  study  of  the  methods  of  spraying  plants  for  the 
control  of  insect  pests  and  fungous  diseases. 

11A.  Ontogeny  of  Insects.  A  detailed  study  of  the  genesis  of  the 
insect  structure. 

11B.  Phytogeny  of  Insects.  The  genealogy  of  insects  and  the  study 
of  classification  in  the  light  of  evolution. 

12.  Advanced.  Laboratory  Work.  Each  term  a  different  line  of 
advanced  study  will  be  offered  in  this  course,  and  individual  work  will  be 
arranged  for  those  desiring  to  begin  research  work. 

23A.  Entomological  Literature.  A  seminary  course  for  conference 
between  students  engaged  in  bibliographical  study. 

23B.  Laboratory  Conference.  A  seminary  course  prescribed  for  all 
students  taking  Courses  12  or  24,  designed  for  mutual  assistance  in  the 
work  under  way  in  the  laboratory. 

24.  Research  Work.  Individual  investigation  under  the  direct 
supervision  of  the  instructor,  but  not  necessarily  at  Berkeley  nor  in 
term  time.  Credit  will  only  be  given  on  the  basis  of  work  ready  for 
publication. 


liu 


UNIVERSITY  EXTENSION  IN  AGRICULTURE. 


The  Department  of  University  Extension  in  Agriculture  has  here- 
tofore confined  itself  to  Farmers'  Institutes.  With  this  publication 
it  begins  work  of  a  somewhat  wider  scope.  The  College  of  Agriculture 
and  the  Agricultural  Experiment  Station  have  from  the  beginning- 
striven  to  serve  the  people  in  every  part  of  the  State,  and,  while  pro- 
viding laboratories  at  Berkeley  for  the  study  of  agricultural  problems, 
and  class  rooms  where  the  young  people  of  the  State  may  come  for 
instruction,  they  have  also  endeavored  to  extend  their  influences  into 
every  community.  These  efforts  may  be  grouped  into  the  following 
classes: 

1.  Correspondence  with  individuals  in  answer  to  requests  for  infor- 
mation on  agricultural  problems. 

2.  Publications,  based  on  studies  made  by  members  of  the  Station 
staff.  These  are  sent  free  of  charge  to  residents  of  the  State  applying 
therefor. 

3.  Lectures  before  public  meetings:  Farmers'  Institutes,  or  other 
gatherings  representing  agricultural  interests. 

4.  Reading  Courses,  like  that  outlined  in  the  present  circular. 

5.  Personal  Visits  by  members  of  the  staff  to  regions  where  problems 
of  great  importance  arise. 

6.  Cooperative  Experiments,  conducted  by  individuals,  working 
under  the  advice  and  generally  the  personal  supervision  of  a  member 
of  tne  Station  staff. 

7.  Investigations,  involving  the  residence  for  some  time  of  a  repre- 
sentative of  the  University  in  the  locality  where  the  problem  in  hand 
may  be  best  solved. 

8.  Substations,  which  are  established  in  regions  where  there  is  a 
variety  of  problems,  requiring  years  for  their  solution,  making  a  rather 
permanent  equipment  necessary  and  the  continuous  residence  of  a  Sta- 
tion man. 

To  this  list  should  be  added  the  increasing  number  of  graduates  of 
the  Agricultural  College,  who  are  farming  in  many  parts  of  the  State, 
and  who  should  be  and  who  are  centers  of  influence  for  University 
ideals. 

The  location  of  the  College  and  Station  at  Berkeley  has  been  fortu- 
nate in  that  it  favored  the  development  and  this  broad  conception  of 
their  opportunities  and  duties  toward  the  State  at  large. 


Printed  at  the  State  Printing  Office,  W.  W.  Shannon,  Superintendent. 


